[Revised entry by Robert Johnson and Adam Cureton on July 7, 2016.
Changes to: Main text, Bibliography]
Immanuel Kant (1724 - 1804) argued that the supreme principle of morality is a standard of rationality that he dubbed the "Categorical Imperative" (CI). Kant characterized the CI as an objective, rationally necessary and unconditional principle that we must always follow despite any natural desires or inclinations we may have to the contrary. All specific moral requirements, according to Kant, are justified by this principle, which means that all immoral actions are irrational because they violate the CI. Other...